This relates generally to imaging devices, and more particularly, to imaging devices having pixels with infrared radiation-blocking layers.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an electronic device is provided with an array of image pixels arranged in pixel rows and pixel columns. The image pixels contain a photodiode for generating charge in response to light. Circuitry is commonly coupled to each pixel column for reading out image signals from the image pixels.
In certain applications, pixels may be exposed to infrared radiation. Infrared light in the environment may be received by pixels. Components of an imaging device may generate infrared radiation that reaches the pixels. Underlying metal structures in an image sensor such as a backside redistribution layer may reflect infrared light received by the sensor back towards the photodiodes, causing the photodiodes to generate photocurrent in response to light that would not normally be detected. Signals generated in response to infrared light reflected off of metal layers in the image sensor and infrared radiation can cause the sensor to generate a “ghost” image of the underlying metal layers.
It would therefore be desirable to provide imaging systems with infrared radiation-blocking structures.